Fix va_arg for doubles. With this patch VAARG nodes always contain the

correct alignment information, which simplifies ExpandRes_VAARG a bit.

The patch introduces a new alignment information to TargetLoweringInfo. This is
needed since the two natural candidates cannot be used:

* The 's' in target data: If this is set to the minimal alignment of any
  argument, getCallFrameTypeAlignment would return 4 for doubles on ARM for
  example.
* The getTransientStackAlignment method. It is possible for an architecture to
  have argument less aligned than what we maintain the stack pointer.

llvm-svn: 108072

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index e1e5a80678b..e60a2b14f1f 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -539,6 +539,10 @@ ARMTargetLowering::ARMTargetLowering(TargetMachine &TM)
 
   maxStoresPerMemcpy = 1;   //// temporary - rewrite interface to use type
 
+  // On ARM arguments smaller than 4 bytes are extended, so all arguments
+  // are at least 4 bytes aligned.
+  setMinStackArgumentAlignment(4);
+
   if (EnableARMCodePlacement)
     benefitFromCodePlacementOpt = true;
 }